Overheard: Tech War

Updated Feb. 11, 2011 12:01 a.m. ET

Big tech's guerilla war is heating up. Hewlett-Packard's "Catalyst for Change" promotion—offering 20% off network switches to customers trading in Cisco Systems' "Catalyst" brand—likely contributed to a hit to Cisco's revenue last quarter. But H-P folks shouldn't get smug. Oracle has its own "Cash for Clunkers" promotion offering 50% off servers to those trading in H-P models. Time for investors to strap on their flak jackets.